A Southampton Town zoning board barred the installation of a symbolic Jewish boundary out of sheer anti-Orthodox Jewish prejudice, a new federal lawsuit alleges.

An East End group has been fighting for years to erect an eruv, an extension of the Jewish home that allows Orthodox Jews to carry out tasks on the Sabbath that are otherwise forbidden, such as pushing strollers and carrying keys.

The religious perimeter is demarcated by the placement of small plastic markers at the tops of telephone poles.

But the Suffolk town’s Zoning Board of Appeals ruled this month that the markers — all but invisible from the street — were prohibited because signs of any sort are not permitted to be placed on telephone poles.

Filed yesterday in Brooklyn, the suit quotes language from the ruling in making its claims of discrimination and accuses the zoning appeals board of being “motivated by discriminatory intentions and animus towards observant Jews.”

“The requested variances will alter the essential character of the neighborhood,” the decision reads.

The ruling also tells eruv backers that restrictions on what they can do derive “not from the town’s zoning regulations but from Jewish law,” according to the suit.

The decision also suggests that use of an eruv exploits a religious loophole and is “motivated by the personal desire . . . to be freed from the proscriptions of Jewish law,” according to the suit.

Southampton Town attorney Tiffany Scarlato declined to comment.

Much of New York City is encircled by an eruv that allows Orthodox Jews to move more freely on the Sabbath.